For over a century, scientists from industrialized countries as well as from developing countries have appropriated natural enemies from different regions of the world. These actions have been conducted thus far without compensation to the donor countries for such ‘biological services’. This unrecompensed extraction has been predicated on the basis that biodiversity (including natural enemies) are ‘humankind's common heritage’ (Kloppenburg & Kleinman, 1987). Such a view has been challenged by some social scientists as well as representatives from some developing countries who now question the inequity of global patterns of exchange of and access to plant genetic resources. At issue is the substantial ‘genetic debt’ that the industrialized countries have procured from developing countries and which has remained uncompensated (Fowler & Mooney, 1990). In fact, the agricultures of industrialized countries are characterized by extreme dependence on ‘introduced’ genetic materials from developing countries. Much of this germplasm has been utilized by seed companies from industrialized countries to develop new, high-yielding varieties, often sold back to developing countries at considerable profit. The contradiction in the status of developing countries crop genetic resources as freely available ‘common heritage’ and the status of seed companies’ commercial varieties as ‘private property’ available by purchase has fueled a major geopolitical controversy. This dispute is bound to expand to other activities involving interregional exchange of biological resources. Concern about global environmental changes, the levels of responsibility of industrialized and developing countries in relation to these changes, and the fact that many developing countries are major repositories of biodiversity which play major biospheric roles, are all issues that fuel the controversy.

Hollow-fibre, microencapsulated and twist-tie formulations of the pheromone of the pink bollworm Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) were used in trials conducted in Pakistan from 1985–1988. Early season control of this pest by mating disruption, permitted an average reduction of two applications, of conventional insecticides otherwise required to control the cotton pest complex, particularly at the time of flower and fruit setting when beneficial insects are most numerous. The pheromone formulations, together with a mixture of selective and broad-spectrum insecticides in plots of 5 or 10 ha of cotton were compared with plots of cotton, of similar size in the same locality treated with a conventional insecticide spray programme and in plots where no insecticide applications were made for the control of bollworms. Comparisons of numbers of infested bolls and estimated yields showed that levels of control achieved using the pheromone/insecticide combinations were equal in effect to conventional programmes of insecticide sprays, whereas in plots where no bollworm control measures were taken, significantly higher bollworm infestations and reduced yield estimates were recorded.

Culex pipiens Linnaeus larvae were collected from various locations in Italy and colonized as separate strains. These were analysed for elevated nonspecific esterase activity and frequency of altered acetylcholinesterase (AChE) mechanisms of insecticide resistance, and bioassayed, to define the cross-resistance spectra conferred by these to organophosphorus and carbamate insecticides. These mechanisms were further characterized by polyacrylamide gel electrophoresis. Elevated esterase A1 (formerly known as Est 3A) which predominated in C. pipiens from Italy in 1985 had been replaced by two esterases, A2 and B2. Altered acetylcholinesterase was still present at high frequencies. Altered and normal acetylcholinesterase were distinguished by differential mobility on polyacrylamide gel electrophoresis. Levels of insecticide resistance were higher in the Lucca region of Italy than in other areas sampled, in response to intensive use of temephos and to a lesser extent chlor-pyrifos, employed to reduce mosquito biting nuisance to tourists in this area.

In 1988/89 the nature and degree of hyperparasitism in two newly introduced parasitoids of exotic mealybug plant pests were examined in Togo. Associated with Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) (cassava mealybug) five indigenous hymenopterous hyperparasitoids were found adapted to the primary parasitoid Epidinocarsis lopezi (De Santis): Chartocerus sp. A (Signiphoridae), Prochiloneurus insolitus (Alam), P. aegyptiacus (Mercet) (Encyrtidae), Tetrastichus sp. (Eulophidae), and Marietta leopardina Motschulsky (Aphelinidae). The rate of hyperparasitism varied considerably (20–90%). At one sampling site Chartocerus sp. A was most frequent (52%), at the other site P. insolitus was found to dominate (55%). The same hyperparasitoids were associated with Rastrococcus invadens Williams (Hemiptera: Pseudococcidae), but with an additional Chartocerus (sp. B). Hyperparasitism ranged from 56 to 86%, with Chartocerus sp. A being the most important species. Multiple parasitism was observed on several occasions. In spite of generally high hyperparasitism, no detrimental effect on the control efficiency of either primary parasitoid was noticed.

In host specificity tests using 81 plant species from 27 families, an undescribed Chrysolina sp. completed its development only on Chrysanthemoides monilifera, a serious weed of native vegetation in Australia. Minor exploratory feeding, mostly by adults, occurred on 35 plant species. The Chrysolina sp. is restricted to the eastern Cape Province of South Africa where it occurs on Chrysanthemoides m. pisifera, a subspecies not yet recorded in Australia. Chrysanthemoides m. monilifera and C. m. rotundata, both naturalized in Australia, were accepted as hosts by Chrysolina sp., but adult emergence was lower on the latter subspecies. A climate comparison between a site location for Chrysolina sp. and stations within the Australian distribution of Chrysanthemoides monilifera has identified potential release sites that may be suitable for the insect. Chrysolina sp. was approved for release in Australia in 1989 and releases were initiated in 1990.

Genetic systems have been developed in several insect species for separating males and females prior to releasing sterilized males in pest control programmes using the sterile insect technique. The systems generally depend on translocating a readily selectable gene onto the Y chromosome. A potential source of instability in such a system is genetic recombination in the male. Although such recombination was originally thought to be absent in most cyclorrhaphous Diptera, low levels have recently been found. We have developed a computer model which simulates the progression of instability in the presence of male recombination, which can be used to assess the influence of rate of recombination in combination with a range of associated genetic and biological parameters. Male recombination alone or fitness of the Y-linked translocation were found to contribute relatively little to the rate of progression of instability. By contrast reduced fitness or mating competitiveness associated with the selectable gene had a strong effect. The sex ratio and the ratio of carriers to non-carriers of the selectable gene showed patterns characteristic of the parameters modelled. The relevance of such data to the development of suitable strains for genetic sex-separation and the replacement of strains under mass rearing conditions are discussed.

Schembria eldana, a new species of goniine Tachinidae, is described (both sexes) from north-eastern Natal, South Africa, where it is parasitic on larvae of the sugarcane borer, Eldana saccharina Walker, in Cyperus papyrus umbels. The genus Schembria Rondani was previously known only from two females of S. meridionalis Rondani from Malta and Israel.

Infestations of pink bollworm, Pectinophora gossypiella (Saunders), (Lepidoptera: Gelechiidae), and numbers of beneficial insects in two cottons, Gossypium hirsutum, were compared at Maricopa, Arizona, and Brawley, California, during the 1986–1988 seasons. Plots (0.8 ha) of WC-12NL (nectariless, okraleaf, and early maturing) had significantly lower boll infestations than DPL-61 (nectaried, normal leaf, and later maturing) for each location and year. The three year average (range) PBW/100 bolls for WC-12NL and DPL-61 at Maricopa were 6.8 (5.7–10.7) compared to 11.2 (6.8–15.7), respectively. At Brawley the averages were 18.9 (9.3–27.6) compared to 39.2 (15.5–52.5), respectively. With the exception of 1986 at Maricopa, the percentage of bolls with eggs was significantly greater for DPL-61 (average 8.1, range 3.4–16.0) than for WC-12NL (average 4.2, range 1.1–12.1) for each location and year. Both cottons averaged about four eggs per oviposited boll; not significantly different. The numbers of Lygus spp. and three beneficial species of insects were not different in the two cottons. Collops vittatus (Say) (Coleoptera: Melyridae) was collected in significantly greater numbers in WC-12NL (1.0 per 50 sweeps compared to 0.9 for DPL-61), while Hippodamia convergens (Guérin-Ménéville) (Coleoptera: Coccinellidae) was collected in greater numbers in DPL-61 (0.6 per 50 sweeps compared to 0.3 for WC-12NL). WC-12NL is the culmination of a 20-year breeding programme for resistance to P. gossypiella and has characteristics attractive for cotton production in areas where a shorter growing season is desirable.

Growth of larvae of the whitefringed weevil, Graphognathus leucoloma (Boheman), was studied in the laboratory and on various crops in pots in a shadehouse at Kairi, on the Atherton Tableland in north Queensland. In the laboratory at 25.5 ± 1°C there were 11 instars for which head capsule widths and weights were recorded. The first instar weighed 0.14 mg. This was a non-feeding stage capable of prolonged survival, and after 10 weeks in soil without food 60% survived. When provided with carrot (Daucus carota) larvae grew to 2 or 3 mg after 6 to 7 weeks, then increased rapidly in weight reaching 140 mg after 120 days. At 25.5°C the average time from first instar to adult was 311 days, due in part to a long prepupal period. Larval growth was measured on the roots of peanut (Arachis hypogaea) plants in pots in summer and winter. Under summer conditions (mean soil temperature 23.3°C) larvae reached 140 mg in about 120 days, similar to that in the laboratory on carrot. These fully grown larvae remained in the pots over the mild winter without pupating. Larvae developing in autumn/winter grew more slowly, but the fully grown larvae were then exposed to high spring (early summer) temperatures and soon pupated, the average time from first instar to adult being 273 days. The indications are that temperatures above 25°C quickly precondition mature larvae from Tolga for pupation, thus explaining the broad timing of adult emergence in the field in north Queensland. On different plants common near Tolga, larvae grew most quickly on peanuts and on the pasture legumes dolichos (Lablab purpureus) and stylosanthes (Stylosanthes guianensis). Survival on maize equalled that on peanuts (46.5% in sterilized soil) but growth was less. Larval survival and growth on the grass crowsfoot (Eleusine indica), and (surprisingly) on the pasture legume glycine (Neonotonia wightii) was very poor.

Megaselia arietina Disney sp. n. is described from Yugoslavia and Israel. Its larva leaf-mines chickpeas, Cicer arietinum. In Macedonia, recorded rates of infestation varied from 48.5–74.8% of the available leaves on a plant, with more than 60% of the leaves in a plot being typical. These levels of infestation seem to be related to the poor yields from the affected plots. The leaf-spot fungus Ascochyta rabiei (Coelomycetes) and the rust fungus Uromyces ciceri arietini (Uredinales) contribute to these reduced yields. The Uromyces spores are ingested by the female flies, but they are carried on the labella of the males without being ingested.

The comparative influence of Busseola fusca (Fuller) and Chilo partellus (Swinhoe), both as separate and mixed populations, on growth and yield of grain sorghum was investigated in a field experiment, using an artificial infestation in cages. C. partellus was more injurious than B. fusca as indicated by whorl damage, stalk injury and yield loss. In the case of mixed populations, dispersion of larvae and damage were independent of B. fusca numbers. A regression equation, Logit Y = 0.24 + 2.06 logit x, relating visible plant damage to yield loss was determined. Control strategies in the case of mixed stem borer populations should be directed against C. partellus.

Field experiments were conducted in the dry season of 1985–86 and the first and second rainy seasons of 1986 at Ibadan, Nigeria, to assess the level of damage and yield reductions caused by Eldana saccharina Walker to maize. Grain weight per plant in artificially infested plots was up to 36% lower than grain weight per plant in insecticide-protected plots. Artificially infested plots had significantly lower 100-grain weight than insecticide-protected ones. The regression coefficient obtained from covariance analysis revealed that 100-grain weight decreased by 0.125 g for each unit increase in the percentage of the stem tunnelled. Infestations of E. saccharina were found to increase significantly the incidence and severity of stalk rots.

During initial screening of the synthetic pyrethroid lamdacyhalothrin (PP 321) at a concentration of 44 and 22 mg/l and applied as a 30 ml drench over each plant against third to fourth instar cutworms, Agrotis segetum (Denis & Schiffermüller) in microplots, few died but they did not damage the plants. Reducing the concentrations to 11 and 5.5 mg/l increased mortality and plant damage. When A. segetum were confined on soil treated with the insecticide at concentrations of 22, 11 and 5.5 mg/l and sprayed at an equivalent rate of 500 l/ha, they all died within one day. The higher concentrations appeared to have a repellent and/or antifeedant effect, and it has been possible to reduce the concentration of lamdacyhalothrin to 12.5 mg/l (≡5.6g a.i./ha) for the drench treatment without risking economic plant damage. For insecticides that have repellent and/or antifeedant properties, it should be possible to balance lower concentrations with adequate protection of plants from pest damage.

This study demonstrates that only a proportion of Lucilia cuprina (Wiedemann) females, which have fed exclusively on sheep dung collected from spring improved pastures, are able to mature a complement of oocytes at the cost of high resorption. Fifty percent of females developed mature oocytes after 11 d of continuous feeding on sheep dung. After 14 d feeding, 80% of females had matured an average of 143 eggs. Females given ad lib access to sheep's liver developed mature oocytes within 2–3 d feeding, producing an average of 223 eggs. Results show that sheep dung is a resource used by L. cuprina adults, but by itself appears to be a poor source of protein for field females to mature oocytes. Females given continuous access to dung collected from sheep 18 h after being drenched with ivermectin, were virtually unable to develop oocytes beyond the resting stage after 10 d feeding. Female adults in particular, became distended with fluid over successive days feeding and both sexes suffered significantly higher mortality compared with adults fed on untreated sheep dung. Knowledge on the feeding frequency and amounts of sheep dung ingested by L. cuprina adults may enable an assessment of the potential for manipulation of ivermectin treatment in a control strategy.

Female oriental armyworm moths, Mythimna separata (Walker), emerged without discernible oocytes in the ovarioles, and reproductive maturity, on the criterion of onset of calling behaviour, was associated with an intermediate stage of oocyte development. Ingestion of carbohydrate was required for completion of oocyte development in the majority of females although a proportion matured when allowed only water. Among females kept alone, these were exclusively moths from a strain selected for early onset of calling but, in the presence of a male, a few females from an unselected line also called and achieved oocyte maturation, without access to carbohydrate. Thus factors other than ovarian development apparently influence the commencement of calling. The absence of an effect of carbohydrate uptake on pre-calling period supports a previous conclusion that this trait is determined primarily by genetic components in this species. It is concluded that ingestion of carbohydrate is important for the attainment of reproductive maturity in M. separata but that it has a differential effect in early and later-calling genotypes. The implications of the results for the reproductive and migratory strategies of M. separata, an important agricultural pest, are discussed.

Previous work demonstrated the potential of the staphylinids Tachyporus hypnorum (Fabricius), T. chrysomelinus (Linnaeus), T. obtusus (Linnaeus) and Philonthus cognatus (Stephens) to feed on the grain aphid, Sitobion avenae (Fabricius). However, gut dissection and observations of foraging behaviour showed that mycophagy could be a factor influencing the potential of Tachyporus spp. to control aphids. The main fungal material detected in the guts of Tachyporus spp. was spores (conidia) of Erysiphe spp. (powdery mildews). In the present study, numbers of conidia (pustules of mildew on leaf-sections) were offered with aphids in food-choice experiments to test how fungal food affected feeding on aphids by these staphylinids. An index of food preference was calculated for each species, sex and for two age classes of larvae, based on the number of conidia and aphids remaining after feeding. Results showed a preference for mildew conidia by T. hypnorum, no preference by T. chrysomelinus and Tachyporus spp. larvae and a preference for aphids by T. obtusus and P. cognatus (adults and larvae). Food-preferences compared well with dietary composition in recent studies of field collected staphylinids. Futhermore, a functional response was detected to increasing numbers of mildew conidia presented (in mildew only consumption-rate experiments) and to the increase in total food density in food-choice experiments. Mycophagy limited aphid predation and explained the numerical response of staphylinid beetles to areas of cereals with high aphid densities, whilst, in other studies, the proportion of aphids eaten by those beetles did not increase.